Wireless Access

Frequent Contributor II

AP booting process

I have managed my wireless network for 7/8 years, last week we were migrating from M1 to M3 on my master controller, in the meanwhile some of my AP were down and they couldn't get up again because they couldn't reach the master (it was down due to MI to M3 migration), the cuestion is:


Can an campus AP boot up whitout a master controller?


I have statically configured the master and serverip commands in all my AP, but even setting up "setenv serverip  ip-of-local-controller" my AP are not able to boot up if it can't reach a master.


Is it normal??

Accepted Solutions

Re: AP booting process

As a summery of this i was able to figure out what was the issue or his concern about it...


Like  i said before he had

1 Master



1 local in the central office

1 local in the remote office


Local controller in the central site got 98 APS, and just can handle 128 aps at total.... on the remote SITE he has a way more APS... so even if he could fail over he wouldnt be able to have them all up, now he knows that.


Now  he was asking why the APS on the remote site were all down


Situation was the fallowing


HE took the M3 master on the central site which is the master

At that time there is power outage on the Remote Site

All APS goes down


When the reboot they foudn that there is no local controller becasuse as i far i understood maybe its damaged...

The APS just got the Informaiton in the NVRAM which is the ip address of the master, his ip address mask master ip address and that kind of thing....

But the information that he has on the RAM whichis the profiles and all that is gone...

Since the AP system profile got gone whent he AP rebooted and foudn that his master controller is down, he was not able to download any profiles or anything anywhere... because he does not have that config...  and that was the thing and thats what he was asking.


Anyways guess this is all




Project engineer

View solution in original post

All Replies

Re: AP booting process


If the AP will not be able to reach the new controller - you will not see it UP.

[if u change AOS - the ap need to get the new AOS from the controller via tftp]


here some info reagarding ADP:

Aruba AP Discovery Process

一、Aruba ADP

Once the AP receives the IP address of the master controller, the AP uses this address as the IP address of a TFTP server and downloads its software image.  After the AP completes the download of its image, it repeats the boot-up process to obtain the same IP address of the master controller for bootstrapping/obtaining its configuration.
The ADP protocol is the first method that all Aruba APs will use to discover the master. The ADP protocol works as follows:
1  AP sends out a discovery packet
2  Master responds with its own loopback address – local controllers .may also respond with the loopback address of the master
3  AP connects to the correct controller and downloads its configuration as well as any new firmware
4  AP reboots and goes operational with correct configuration


1  Auto Discovery Protocol (ADP) – broadcast 

In the broadcast version of ADP, an Aruba AP sends out broadcast packets using the broadcast address  The master or local controllers will then respond to the AP with the master loopback address.


Important:  This method requires the master or other controllers to be located on the same Layer 2 network as the AP.


(Aruba2400) (config) #adp discovery enable
(Aruba2400) (config) #adp igmp-join disable


2  Auto Discovery Protocol (ADP) -  multicast 

With the multicast version, an Aruba AP sends out IP multicast packets using the group address The controllers will reply to the AP with its own loopback IP address.  


This method requires the network to correctly pass multicast traffic between the AP and the controllers. 


(Aruba2400) (config) #adp discovery enable
(Aruba2400) (config) #adp igmp-join enable


3  Dynamic Host Configuration Protocol (DHCP Option 43)

DHCP servers are a popular way of configuring clients with basic networking information such as an IP address, a default gateway,
network mask, DNS server, etc. Most DHCP servers have the ability to also send a variety of optional information as well. One of these is the Vendor-Specific Option Code, often called option 43. 
Here is how option 43 works:
1  The DHCP client on an Aruba AP adds an optional piece of information called the Vendor Class Identifier Code (Option 60) to
its DHCP request. The value of this code is ArubaAP
2  The DHCP server sees the vendor information and checks if it has option 43 configured, if it does, it will send the Vendor-Specific
Option Code (43) to the client. The value of this option is the loopback address of the Aruba master
3  The AP gets a response from the DHCP server and checks if option 43 was returned, if it was, the AP contacts the master using the
supplied IP address


4  Domain Name Services – DNS lookup
In most cases this is the most popular discovery method. It has the advantage of working very well across both Layer 2 and Layer 3
networks.  If an Aruba AP fails to receive the IP address of the master controller via DHCP or either ADP method, the AP will use the IP
address of the domain name server it received from DHCP to perform a DNS lookup.  


This method requires a DNS host entry that corresponds to the name of the master. By default, APs look for the entry aruba-master.


二、AP Boot Sequence

Aruba AP Dynamic boot sequence

1 AP learns AP Name / AP Group from bootrom
2 AP sends out DHCP request for IP address
3 If DHCP response includes vendor option 43 (masterip), AP will use this for Master IP address
4 If no vendor option specified, AP sends “ADP” packet to Multicast group
5 If no response to Multicast ADP, AP sends “ADP” packet as L2/L3 broadcast (configure Master Aruba controller as a DHCP helper recipient)
6 If no response, AP sends DNS query to server given by DHCP for “aruba-master.domain.com” where “domain.com” is domain given by DHCP.  AP will use this for Master IP address

Once AP determines Master IP address, boot continues from Step 2 in Static config


AP Static boot sequence
1 AP loads variables from bootrom
2 AP sends message to Aruba controller with its AP Name / AP Group
3 If needed, AP sends an TFTP request to Aruba controller and downloads OS image (establish PAPI (UDP 8211 )连接到无线交换机) (control Protocol)
4 Based on the AP Name / AP Group, the current controller may take control of this AP or direct it to another controller
5 AP authenticates to controller and establishes GRE tunnel

 client 与 AP 通信,AP将数据通过 GRE tunnel   传送到无线控制器



adp discovery {disable|enable} igmp-join {disable|enable} igmp-vlan <vlan>


(host) #show adp config

ADP Configuration
key        value
---        -----
discovery  enable
igmp-join  enable
igmp-vlan  0


Some Aruba AP boot\pre-boot command syntax examples:


Pre-boot Commands:


apboot> help
?              - alias for 'help'
boot           - boot the OS image
clear          - clear the OS image or other information
date           - get/set/reset date & time
dhcp           - invoke DHCP client to obtain IP/boot params
factory_reset  - reset to factory defaults
help           - print online help
mfginfo        - show manufacturing info
ping           - send ICMP ECHO_REQUEST to network host
printenv       - print environment variables
purgeenv       - restore default environment variables
reset          - Perform RESET of the CPU
saveenv        - save environment variables to persistent storage
setenv         - set environment variables
tftpboot       - boot image via network using TFTP protocol
upgrade        - upgrade the APBoot or OS image
version        - display version


Environment Variables:


bootcmd=boot ap



Hope it will give u some idea.

if this post helped u - please mark as a sultion and K+ [the star button]   :catindifferent: thanks :]

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Re: AP booting process

More info:




First of it the AP need Information for his boot process and Informations about the Controller where he should connect. This Informations are Enviroment Variables. This are the only Parameters that are stored on the AP. You can show them with the printenv command. Example:

apboot> printenv
bootcmd=boot ap
name=AP70 MeshPoint

fqln=AP70 MeshPoint.Floor 1.New Building.Weisser Riese

After boot and connecting to the Controller the Ap loads some more Informations:

BSSID 00:1a:1e:ed:38:c0
LMS IP x.x.x.x
Master IP y.y.y.y
Mode AP Mode
QBSS Probe Response Allow Access
Native VLAN ID 1
SAP MTU 1500 bytes
Heartbeat DSCP 0
High throughput enable (radio) Disabled
Channel 6
Beacon Period 100 msec
Transmit Power 14 dBm
Advertise TPC Capability Disabled
Enable CSA Disabled
CSA Count 4
Management Frame Throttle interval 1 sec
Management Frame Throttle Limit 20
VoIP Aware Scan Disabled
Power Save Aware Scan Enabled
Load aware Scan Threshold 1250000 Bps
Country Code DE
Encryption wpa2-aes
WPA2 Pre-Auth Disabled
DTIM Interval 1 beacon periods
802.11g Basic Rates 11 12 18 24 36 48 54
802.11g Transmit Rates 11 12 18 24 36 48 54
Station Ageout Time 1000 sec
Max Transmit Attempts 15
RTS Threshold 2333 bytes
Short Preamble Enabled
Max Associations 25
Wireless Multimedia (WMM) Disabled
WMM TSPEC Min Inactivity Interval 0 msec
DSCP mapping for WMM voice AC N/A
DSCP mapping for WMM video AC N/A
DSCP mapping for WMM best-effort AC N/A
DSCP mapping for WMM background AC N/A
Hide SSID Disabled
Deny_Broadcast Probes Disabled
Local Probe Response Enabled
Battery Boost Disabled
Maximum Transmit Failures 32
BC/MC Rate Optimization Disabled
Forward mode tunnel

You can see that there are no Informations that are confidential.
After that the AP builds a Tunnel for every configured WLAN to the Controller.
The tunnels are used to send all Traffic to the Controller.

On the Controller all Traffic is decrypted. After that it is passing the Firewallengine, ARP Table,.......

The remote AP saves configuration information that allows it to
operate autonomously using one or more SSIDs in local bridging mode while
supporting open association or encryption with PSKs.


if this post helped u - please mark as a sultion and K+ [the star button]   :catindifferent: thanks :]

*****************2Plus Wireless Solutions****************************
Aruba Airheads - Powered By community for empower the community
************ Don't Forget to Kudos + me,If i helped you******************
Frequent Contributor II

Re: AP booting process

The following events happened:

My AP was already up and working fine, it is statically configured before plug into the network with:


    setenv ipaddr  "ip ap"

    setenv master   "ip mastercontroller"

    setenv serverip  "ip mastercontroller"


so, we don't use ADP, DNS or DHCP to get the AP own ip or master ip. Once the AP contact the master, it gets LMS ip = local controller ip (different from the master), then the master is going down an also the AP, but after going down, the AP is unable to properly reboot.


The AP doesn't need to get any new AOS because it has the correct one and is closing the tunnel with a local controller different from the master, so why is it unable to go up?, does it need to reach the master for something?




Re: AP booting process

Send a screenshot of your LMS/BACKUP LMS settings in the ap-system profile that belong to the AP-Group you trying to provisin the AP to.
*****************2Plus Wireless Solutions****************************
Aruba Airheads - Powered By community for empower the community
************ Don't Forget to Kudos + me,If i helped you******************

Re: AP booting process

1-What AP models you got that are not going up?

2-are the all the same model?

3-What firmware you got on those M3?

4-Are tthey APS that not going up RAPS?

5-On the APS that are working do show print

6-On the aps that arent working do show print also on AP console.


Also if you can when you consoling copy and paste the boot process to see whats happening.



Project engineer

Re: AP booting process


setenv ipaddr
setenv netmask
setenv gatewayip
setenv serverip
setenv master
thats an example... i see you just putting the ip of the AP... im assuming you did just that.... and didnt change the gateway and netmask  or didnt set it.... if you did all that then forget this post. :)


Project engineer

Re: AP booting process

Print for us some screenshots of the LMS/BACK LMS settings u did - AP system profile

and also the AP-GROUP settings.+ AP installation page [from the GUI]


or of u preferred copy&paste CLI outputs.


It will help us help u :smileyhappy:

*****************2Plus Wireless Solutions****************************
Aruba Airheads - Powered By community for empower the community
************ Don't Forget to Kudos + me,If i helped you******************
Frequent Contributor II

Re: AP booting process

ap system-profile "cierre_tunel_Desam_backup12.5"
   bootstrap-threshold 30
   request-retry-interval 15
   max-request-retries 15
   keepalive-interval 80


ap-group "O11-Biblioteca"
   virtual-ap "perfil_red_eduroam"
   virtual-ap "perfil_red_Iumhnet"
   virtual-ap "perfil_red_Iumhweb"
   ap-system-profile "cierre_tunel_Desam_backup12.5"
   dot11a-traffic-mgmt-profile "perfil_preferred_access"
   dot11g-traffic-mgmt-profile "perfil_preferred_access" is my local controller is a VRRP ip shared between the master controller and other controller different from 208.7.


If the master controller is down ( I also can reach and I reboot AP from Ap-group O11-Biblioteca, those ap can't go up and running

Frequent Contributor II

Re: AP booting process

setenv ipaddr

setenv netmask
setenv gatewayip
setenv serverip
setenv master


This is the config I normally use statically to one AP, is the VRRP ip shared between my master controller and another local controller, being master controller the active for the VRRP group.

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